LOCATION WALSTEAD MTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Typic Haplustolls
TYPICAL PEDON: Walstead gravelly loam, cultivated (colors are for dry soil unless otherwise noted).
A1--0 to 8 inches; dark gray (10YR 4/1) gravelly loam, black (10YR 2/1) moist; moderate medium granular structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine roots; many fine and very fine pores; 20 percent gravel and 5 percent cobbles; neutral (pH 7.0); clear wavy boundary. (6 to 9 inches thick)
AB--8 to 15 inches; brown (10YR 5/3) very gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many fine and very fine pores; 30 percent gravel and 5 percent cobbles; neutral (pH 6.8); clear wavy boundary. (4 to 7 inches thick)
Bw1--15 to 22 inches; yellowish brown (10YR 5/4) very gravelly loam, brown (10YR 4/3) moist; weak medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine roots; common fine pores; 35 percent gravel and 5 percent cobbles; neutral (pH 6.8); gradual wavy boundary. (5 to 8 inches thick)
Bw2--22 to 36 inches; pale brown (10YR 6/3) very gravelly loam, brown (10YR 4/3) moist; weak medium and coarse subangular structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; common fine pores; 50 percent gravel and 10 percent cobbles; neutral (pH 7.0); gradual smooth boundary. (8 to 15 inches thick)
Bk1--36 to 44 inches; very pale brown (10YR 7/3) very gravelly loam, grayish brown (2.5Y 5/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; 50 percent gravel and 10 percent cobbles; disseminated lime; violently effervescent; moderately alkaline (pH 8.2); gradual wavy boundary. (6 to 18 inches thick)
Bk2--44 to 60 inches; very pale brown (10YR 8/2) very gravelly loam, pale brown (10YR 6/3) moist; massive; soft, very friable, slightly sticky and slightly plastic; few fine roots; 40 percent gravel and 10 percent cobbles; disseminated lime; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Lake County, Montana; 1,280 feet north and 175 feet west of the SE corner of sec. 4, T. 18 N., R. 19 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 10 to 16 inches.
Control section - 10 to 25 percent clay and 35 to 60 percent rock fragments.
Depth to calcic horizon - 23 to 39 inches.
Soil phases - stony and very stony.
A horizon - Value: 3, 4, or 5 dry; 2 or 3 moist
Chroma: 1 or 2
Texture: loam, silt loam
Clay content: 15 to 27 percent
Rock fragments: 15 to 60 percent--0 to 15 percent stones and cobbles; 15 to 45 percent gravel; stony phase--5 to 20 percent stones and cobbles; 10 to 15 percent gravel; very stony phase--10 to 25 percent stones and cobbles; 10 to 15 percent gravel
Reaction: pH 6.6 to 7.8
AB horizon - Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture: loam, silt loam
Clay content: 15 to 27 percent
Rock fragments: 25 to 45 percent--5 to 15 percent stones and cobbles; 20 to 30 percent gravel
Reaction: pH 6.6 to 7.8
Bw1 horizon - Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3, or 4
Clay content: 15 to 27 percent
Texture: loam, silt loam, or sandy loam
Rock fragments: 35 to 60 percent--5 to 25 percent stones and cobbles; 30 to 35 percent gravel
Reaction: pH 6.6 to 7.8
Bw2 horizon - Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4
Texture: loam, silt loam, or sandy loam
Clay content: 10 to 27 percent
Rock fragments: 35 to 60 percent--5 to 25 percent stones and cobbles; 30 to 50 percent gravel
Reaction: pH 6.6 to 7.8
Bk1 horizon - Hue: 10YR or 2.5Y
Value: 7 or 8 dry; 5 or 6 moist
Chroma: 2 or 3
Texture: loam, silt loam, or sandy loam
Clay content: 10 to 27 percent
Rock fragments: 35 to 60 percent--5 to 25 percent stones and cobbles; 30 to 50 percent gravel
Calcium carbonate equivalent: 15 to 30 percent
Reaction: pH 7.9 to 8.4
Bk2 horizon - Hue: 10YR or 2.5Y
Value: 7 or 8 dry; 5 or 6 moist
Chroma: 2 or 3
Texture: loam, silt loam, or sandy loam
Clay content: 10 to 27 percent
Rock fragments: 35 to 60 percent--5 to 20 percent stones and cobbles; 30 to 40 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES:
Aguja (NM) - moderately deep to lithic contact; does not have Bk horizons
Finleypoint (MT) - does not have Bk horizons, has albic and E/Bw horizons
Flott (MT) - does not have a cambic horizon; has E/Bw horizons
Kutler (CO) - moderately deep to paralithic contact; does not have Bk horizons
Labre (MT) - have porcelanite fragments in the particle-size control section
Perma (MT) - does not have Bk horizons
Peso (NM + WY)- moderately deep to a lithic contact
Renegade (UT) - deep to a paralithic contact; does not have Bk horizons
Sandia (NM) - deep to a lithic contact; does not have Bk horizons
Slimbutte (SD) - has free carbonates at 10 to 16 inches
Subwell (MT) - has a lithologic discontinuity at 10 to 20 inches
Towave (UT) - does not have a calcic horizon; has carbonates at 4 to 11 inches
Veatch (CO) - moderately deep to a lithic contact
Vigilante (MT) - deep to a lithic contact; does not have Bk horizons
Wanagan (ND) - has a lithologic discontinuity at 14 to 30 inches
Wimper (MT) - has Bk horizons at 10 to 15 inches
GEOGRAPHIC SETTING: The Walstead soils are on dissected alluvial fans, stream terraces, moraines, outwash terraces, eskers and glaciated mountain slopes. Elevations are 2,790 to 5,000 feet. Slopes are 0 to 65 percent. These soils formed in calcareous till or alluvium. The climate is characterized by long, cold winters; moist springs; and warm summers. Mean annual precipitation is 17 to 25 inches. Mean annual temperature is 39 to 45 degrees F. The frost-free period is 70 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS:
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Walstead soils are used mainly for irrigated and nonirrigated crops, pastureland, and rangeland. Potential native vegetation is mainly rough fescue and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Walstead soils are of small extent in the mountain valleys of northwestern Montana. MLRA 44.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lake County, Montana, 1991; proposed in Lake County Montana, 1972. Walstead is a place name.
REMARKS: Soil interpretations record: MT0038 and MT0754. Diagnostic horizons and features recognized in this pedon are: a mollic epipedon from the soil surface to 15 inches (A1 and AB horizons); a cambic horizon from 15 to 36 inches (Bw1 and Bw2 horizons); a calcic horizon from 36 to 44 inches (Bk1 horizon); and a particle-size control section from 10 to 40 inches (AB, Bw1, Bw2, and Bk1 horizons). Walstead soils have a frigid temperature regime and an ustic moisture regime.